Hub One drops connection with smart dvr after 15mins

Recently moved to PN from BT. Was using HH5 (type B) with a home network setup to access music, pics etc from a Panasonic DVR. Hub was connected to PC by ethernet and DVR to hub by wireless. All worked fine.

Swopped the hubs, changed nothing else, and now, 15mins after logging the dvr on to the network it loses connection to the hub and I have to reconnect, 15mins later, same again. Time varies a little as it always disconnects between music tracks, or between pictures. This makes me wonder if there is some sort of time out request or something in the hub.

However if I put the BT one back (without internet connected) - no problem. In fact I currently have the BT hub just set up to connect between PC & DVR.

I assume I could use the BT hub only or just carry on as I have it now, but anyone any idea why this is happening?